Myoclonus during prolonged treatment with sertraline in an adolescent patient.

A 15-year-old female adolescent with depression developed myoclonus after uninterrupted treatment with sertraline over 6 years. She was also receiving methylphenidate. Withdrawal of sertraline and continuation of methylphenidate did not result in any improvement. Treatment with valproic acid resulted in improvement of the movement disorder. This report suggests that myoclonus may be a side effect of sertraline in some adolescents. Further, we hypothesized that extended treatment over several years, young age, and a compromised central nervous system due to underlying disorders may be risk factors for the development of this side effect.